Sildenafil 50 DHG medicine treats erectile dysfunction (1 blister x 1 tablet)

Dosage form Box of 1 blister x 1 tablet
Specifications Sildenafil

Ingredient

Composition information	Content
Sildenafil	50mg

Uses

indications

Sildenafil 50 drug is indicated in the following cases:

Sildenafil is used to treat erectile dysfunction, which is the inability to achieve or maintain enough erection to satisfy sexual activity.

ATC code: G04be03.

Sildenafil is Sildenafil's citrate salt, oral to treat erectile dysfunction. Sildenafil has a selective inhibitory effect Guanosin monophosphate ring (CGMP - Cyclic Guuan Monophosphate) - Phosphodiesterase specific phosphodiesterase 5 (PDE5).

Mechanism of action

The penis physiological mechanism leads to the release of nitric oxid (NO) in the cave during the sexual stimulation process.

Then NO activated the Ganylat Cyclase enzyme, which increases the concentration of CGMP, thereby relaxing the blood vessel smooth muscles of the cave and allows blood flow to flow.

Sildenafil does not have the effect of direct relaxation on human isolation, but increases the effect of NO by inhibiting PDE5, this substance has the effect of decomposing CGMP in the cave.

When stimulating sex, creating a NO release on the spot, Sildenafil's PDE5 inhibitors will increase the amount of CGMP in the cave, the result of smooth muscle relaxation and increase blood flow to the cave.

In the recommended dose, Sildenafil only works when there is an accompanying sexual stimulation.

In vitro studies show that Sildenafil selectively inhibits PDE5.

The effect of Sildenafil selected on PDE5 is stronger than other known phosphodiesterase (10 times higher for PDE6,> 80 times for PDE1,> 700 times for PDE2, PDE3, PDE4 and PDE7-PDE11).

Selective effect on PDE5 is 4,000 times stronger than PDE3, this is very important because PDE3 is an enamel related to heart contractions.

Clinical studies

heart

There is no clinical change on the ECG (ECGS) of normal volunteers when using Sildenafil single doses up to 100 mg orally.

After using a 100 mg dose, the systolic blood pressure decreased by an average of 8.3 mmHg and the diastolic blood pressure decreased by the average of 5.3 mmHg (measured in the lying position).

The effects on blood pressure on people who are using nitrate more at the same time are also fleeting.

Research on hemodynamics on 14 patients with severe coronary artery disease (> 70% at least 1 coronary artery) is used for a single dose of 100 mg of Sildenafil that the systolic and diastolic blood pressure decreases by 7% and 6% compared to the blood pressure before taking the drug. The average pulmonary systolic blood pressure decreases by 9%. Sildenafil does not affect the heart supply and does not affect the flow through the narrow coronary arteries, and creates improvement (about 13%) in reversing the artery flow stimulated by adenosin (in both narrow arteries and related arteries).

Double clinical clinical trial has a placebo over 144 patients with erectile dysfunction and stable angina. These patients take anti -angina drugs regularly (except for nitrate). They have to work hard to the limit of angina. In patients with a single dose of 100 mg Sildenafil, the milling time is longer (19.9 seconds; 95%trust range: 0.9 - 38.9 seconds) (statistically significant) compared to patients with placebo. The average effort (adjusted with the basic level) to the angina limit is 423.6 seconds in Sildenafil users and 403.7 seconds in placebo users.

Randomly blind study, with a placebo (with a change of Sildenafil, up to 100 mg) on 568 men with erectile dysfunction and hypertension. These patients always have to take at least two anti -hypertension drugs. Sildenafil results improves 71% erection in Sildenafil users compared to 18% in placebo users. Successful intercourse rate in Sildenafil users 62% compared to 26% in placebo users. The rate of unwanted effects in these patients is similar to other patients, as well as not changing in users 3 or more anti -hypertension drugs.

Smart

Differences in distinguishing light and transient colors (blue/ green) were discovered in some cases using test Farnsworth - Munsell 100 Hue after 60 minutes when taking a dose of 100 mg, and after 120 minutes there was no proven effect. The main mechanism of distinctive change changes related to PDE6 inhibitors. This enamel is abundant in the retina. In vitro studies show that Sildenafil inhibits PDE6 10 times less than PDE5.

Sildenafil has no effect on the flexibility of vision, contrast sensitivity, retinal electro, pressure in the eyes or pupils.

In a controlled horizontal study in patients with degenerative yellow points related to age (n = 9), Sildenafil (single dose, 100 mg) is well tolerated and there is no clinical significance on vision tests (vision flexibility, amsler grid, distinguishing color, traffic light signals, hummphrey market).

Effectiveness

Sildenafil's effectiveness and safety are assessed in 21 randomly blind clinical trials with placebo over 6 months. Over 3,000 patients with erectile dysfunction (19 - 87 years old) in all forms (organized by the organ, psychological, mixed form) are used for Sildenafil. The effectiveness of Sildenafil is assessed by general review questions, erectile diaries, international IIF (International Index of Erectile Function), and questions for patients' sex partners.

The effect of Sildenafil is the ability to achieve and maintain an erection enough to conduct intercourse. This effect has been shown through all 21 studies and was maintained through extended extended studies (over 1 year). In fixed studies, the rate of improvement of erection ability is 62% (with a dose of 25 mg Sildenafil), 74% (with the dose of Sildenafil 50 mg), and 82% (with the dose of Sildenafil 100 mg) compared to 25% in the fake group. In addition to improving erection, Sildenafil also improves pleasure, satisfaction when intercourse and general satisfaction.

Through tests that:

In patients with diabetes, Sildenafil's erection improvement rate is 59% compared to 16% in placebo users. Pharmacy.

Sildenafil is metabolized in the liver (mainly through Cytochrom P450 3A4) and its metabolites have the same activity as the mother (Sildenafil).

absorption

Sildenafil is quickly absorbed after drinking, with absolute bioavailability of about 41% (ranging from 25 - 63%).

On In vitro, the concentration of 3.5 nm Sildenafil inhibits the PDE5 enzyme of the person about 50%. In humans, the maximum free Sildenafil concentration after using a single dose of 100 mg is approximately 18 ng/ ml or 38 nm.

The maximum concentrations achieved in plasma from 30 - 120 minutes (60 minutes on average) are observed when taking the drug when hungry.

Food with high fat content reduces Sildenafil's absorption capacity, with an average time for TMAX's average reduction of 60 minutes and CMAX decreases an average of 29%, on the contrary, the absorption level does not affect significantly (the area below the curve decreases by 11%).

distribution

Sildenafil's average drug distribution (VSS) is 105 l, focusing on tissues.

Sildenafil and the metabolites in its large circulatory round are N-Desmethyl mounted up to 96% to plasma proteins. The attachment to plasma protein does not depend on its total concentration.

Sildenafil's concentration in the semen of healthy volunteers after taking 90 minutes is less than 0.0002% of the dose of use (average 188 ng).

transformation

Sildenafil is metabolized mainly by CYP3A4 (main roads) and CYP2C9 (sub -line) in the liver.

The metabolites in the main metabolic ring of Sildenafil produced from the process N - Desmethylation and then continued metabolism.

These metabolites have a selective activity for PDE similar to Sildenafil and on Vitro in Vitro for PDE5 approximately 50% of the parent substance.

In healthy volunteers, plasma concentrations of metabolic substances are approximately 40% of the mother concentration.

Metabolic N - Desmethyl is metabolized again, with a half -life of 4 hours.

Elimination

Sildenafil's total clearance is 41 l/ hour, with the last half phase time of 3-5 hours.

After oral or intravenous use, Sildenafil is excreted mainly in the form of metabolites (about 80% of oral dose) and in a small part through urine (about 13% of oral dose).

Pharmacokinetics in special patients

Old people

On healthy elderly people (aged 65 and older), Sildenafil's clearance decreases, resulting in Sildenafil concentration and N - Desmethyl activity in plasma more than 90% higher than the concentration of these substances in healthy young volunteers (18 - 45 years old). Due to the cohesion of Sildenafil on plasma proteins depending on the age, the free concentration of Sildenafil in plasma increased by about 40%.

Renal failure

On people with mild kidney failure (creatinine clearance = 50 - 80 ml/ min) or medium (creatinine clearance = 30 - 49 ml/ min), when using a single dose of Sildenafil (50 mg), there is no change in pharmacokinetics.

On people with severe renal failure (creatinine clearance ≤ 30 ml/ min), Sildenafil's clearance is reduced, increasing approximately double the area under the AUC curve (100%) and CMAX (88%) compared to people at the same age but no kidney failure.

In addition, the values of CMAX and AUC of N - Desmethyl metabolites have a significant 200% and 79% significant in severe renal impairment objects compared to normal kidney function objects.

Hepatic failure

On people with cirrhosis (Child - Pugh A, Child - Pugh B), Sildenafil's clearance is reduced, the result increases the area under the AUC curve (85%) and CMAX (47%) compared to people without liver failure at the same age. Sildenafil's pharmacokinetics in patients with severe liver failure (Child - PUGH C) have not been studied.

Before taking Sildenafil 50 DHG medicine treats erectile dysfunction (1 blister x 1 tablet)

How to use

oral tablets. Take the tablet with a glass of water.

Dosage

for adults

Most patients are recommended to take a dose of 50 mg when needed, oral before having sex about 1 hour. Based on the tolerance and effect of the drug, the dose may increase to a maximum of 100 mg or decrease to 25 mg. The maximum recommended dose is 100 mg, the maximum number of times is 1 time per day.

For patients with renal failure

Cases of mild or medium renal failure (Creatinine clearance = 30 - 80 ml/ minute), do not need to adjust the dose.

Cases of severe renal failure (Creatinine clearance

for patients with liver failure

The dose to be used is 25 mg because the clearance of Sildenafil is reduced in these patients (for example, cirrhosis).

For patients who are taking other drugs

Based on the degree of interaction in patients taking Sildenafil simultaneously with Ritonavir, it should not exceed a maximum single dose of 25 mg Sildenafil within 48 hours.

Patients who are taking drugs that inhibit CYP3A4 (for example, erythromycin, saquinavir, ketoconazole, iTraconazole), the starting dose should be used as 25 mg.

To limit the risk of posture hypotension during treatment, patients should be stable treatment when using sympathetic alpha cancellation drugs before starting treatment with Sildenafil. In addition, it is advisable to consider using lower Sildenafil doses at the beginning of treatment.

For children: Not for children under 18 years old.

For the elderly (≥ 65 years old): There is no need to adjust the dose.

or as directed by the physician.

Note: The above dose is for reference only. Specific dosage depends on the condition and level of progression of the disease. For a suitable dose, you need to consult a doctor or medical specialist.What do

do when using overdose?

In case of an overdose, requires appropriate support measures.

Kidney fertilizer does not increase the rate of clearance because Sildenafil is strongly attached to plasma proteins and is not eliminated through the urine.

In case of emergency, call the 115 emergency center immediately or go to the nearest local health station.

What to do when you forget 1 dose? However, if the time to relax with the next dose is too short, skip the dose and continue the calendar of the drug. Do not use double doses to compensate for missed dose.

Side Effects

When using Sildenafil 50 you may experience unwanted effects (ADR):

In general, unwanted effects are just transient, light or medium.

In fixed dose studies, the frequency of some complications increased by the dose.

Studies with fixed dose reflect more than the recommended dose regime. The nature of unwanted effects in these studies is similar to that of studies with fixed doses.

The most commonly reported effects are headaches and blushing.

Classification by agency system Parasitic infection Rhinitis Dizziness dizziness Eyes, dry eyes, eye strain, dazzling, yellowish, redness, eye disorders, conjunctival congestion, eye irritation, abnormal feeling in the eyes, eyelid edema. Blood flushed, hot, hot lower blood pressure Nose

Disorder digestive system Ban Want*, increase erections general disorders and at the place of use Hot sensation irritation

With a larger dose than the recommended dose, the unwanted effects are still the effects listed above, but in general, it will be more encountered.

Through analysis of double blind clinical trials with a placebo, more than 700 people annually use a placebo and 1300 people annually use Sildenafil every year, there is no difference between the two groups in terms of myocardial infarction (MI) and cardiovascular mortality. For both groups, the rate of myocardial infarction (MI) is 1.1 per 100 people every year, while the cardiovascular mortality rate is 0.3 over 100 people every year.

Notify the doctor with unwanted effects when using the drug.

Instructions on how to handle ADR:

Notify the physician with unwanted effects when using the drug.

Warnings

Before using the drug you need to read the instructions carefully and refer to the information below.

contraindicated

Sildenafil 50 contraindicated drug in the following cases:

Contraindicated to use Sildenafil for patients allergies to any ingredients of the drug. Therefore, contraindicated use of sildenafil for patients who are using nitric oxid suppliers, organic nitrates or organic nitrides in any form, whether they are frequent or interrupted. evidence.

Be cautious when using

need to be very careful when taking the drug for patients in the following cases:

Meaned prehistoric and clinical examination to diagnose erectile dysfunction, to identify potential causes and determine appropriate treatment.

Because there may be some cardiovascular risks related to sexual activity, the physician must pay attention to the patient's cardiovascular condition before conducting erectile dysfunction treatment.

Do not use erectile dysfunction drugs in men are recommended not to be sexually active.

Serious cardiovascular events include myocardial infarction, sudden death related to heart disease, disorder, ventricular arrhythmia, cerebral hemorrhage and transient ischemic anemia reported during circulation using Sildenafil to treat erectile dysfunction. Mostly but not all these patients have a history of cardiovascular risk factors. Many of these events were reported immediately after using Sildenafil without sexual activity. Other events reported from a few hours to several days after using Sildenafil and having sex. It is impossible to identify whether these events are directly related to Sildenafil, sexual activity, patients with cardiovascular disease, a combination of these factors or other factors.

Some clinical trials have found that Sildenafil has a systemic vasodilation property that causes transient hypotension. For most patients, it has very little or no effect.

However, before prescribing, physicians must pay attention to patients with pathological conditions that may be affected by this effect and especially when they have more sexual activity. Patients who interfere with left ventricular flow (for example, aortic stenosis, obstructive hypertrophy) or systematic skin atrophy syndrome (syndrome of multiple system atrophy) are patients with hyperactive hyperplasia, manifested by serious decline in the ability to control blood pressure automatically are those who need to consider treatment.

Non -artery anemia neuropathy (Naion), a rare disease and is the cause of vision loss or vision loss, is rare in the circulation process when used with phosphodiesterase inhibitors in group 5 (PDE5), including Sildenafil.

Most of these patients have risk factors such as low visual cup ratio compared to visual disks ("increased visual discs"), over 50 years old, diabetes, hypertension, coronary artery disease, high blood lipids and smoking. A observatory evaluating whether the recent use of PDE5 inhibitors, as a group of drugs, is related to the Naion acute onset. The results suggested that the risk of deion nearly doubled within 5 semi -excreted cycles of PDE5 inhibitors used. Based on the published literature, the annual new incidence of Naion is 2.5 - 11.8 shifts per 100,000 men aged ≥ 50 every year in the general population. In case of sudden loss of vision, it is necessary to advise patients to stop using Sildenafil and consult a doctor immediately.

The person who has been sick in the risk of deaion recurrence increases. So doctors need to discuss with such patients about this risk and whether they are adversely affected if using PDE5 inhibitors. PDE5 inhibitors, including Sildenafil, should be used carefully in these patients and only if the expected benefits are superior to the risk.

Be careful when prescribing Sildenafil for patients who are taking sympathetic alpha drugs because of the indications that can lead to symptomic hypotension in sensitive patients. To limit the risk of posture hypotension, patients should treat hemodynamic stability when using sympathetic alpha drugs before starting sildenafil therapy. Sildenafil should be considered at low doses. In addition, the doctor should advise patients to do what to do in case of posture hypotension symptoms.

A few patients with pigmentation retinitis have phosphodiesterase liver disorders in the retina, need to be cautious when treating Sildenafil in these patients because there is no safety evidence.

Introeted in vitro studies that see Sildenafil have an effect on platelet condenser resistance of sodium nitroprussid (substance for nitric oxid). There is currently no safety information about the use of Sildenafil in patients with blood clotting or acute digestive ulcers, so be cautious in these patients.

Be cautious when prescribing erectile dysfunction agents for patients with deformation of penis anatomy (such as an angle folding penis, cavity fibrosis, or Peyronie disease), patients with pathological diseases that cause penis pain (such as sickle cell anemia, multiple myeloma, leukemia).

There have been reports on prolonged erection and unwanted erection when using Sildenafil after the drug is circulated. In the case of erects that last more than 4 hours, patients need medical facilities for immediate treatment.

If the erectile is not treated immediately, it can lead to the penis tissue that is destroyed and impossible permanently.

Safety and effectiveness of using Sildenafil combining with other PDE5 inhibitors, pulmonary arterial medications containing Sildenafil or other non -researched anti -dysliages, so it should not be combined with these drugs.

Sudden reduction or loss of hearing has been reported in a small number of cases using PDE5 inhibitors, including Sildenafil in clinical trials and after circulation. Most patients have risk factors for sudden reduction in hearing or loss. The causal relationship between the use of PDE5 inhibitors and the loss or loss of hearing suddenly. In the event of a sudden reduction or loss of hearing, the patient is advised to stop taking Sildenafil and see a doctor immediately.

The effect of drugs on driving and operating machinery

has no specific research on the impact on driving and operating machinery.

Dizziness and vision change have been reported in clinical trials with Sildenafil, so patients need to know how they react to Sildenafil before driving or operating machinery.

Use drugs for women during pregnancy and lactation

Do not use Sildenafil for women.

Research on rats and rabbits after taking oral Sildenafil, no evidence of teratogenicity, reduced fertility, or adverse effects for embryo and fetal development.

There are no adequate and appropriate studies on pregnant and lactating women.

Drug interaction

The effect of other drugs on Sildenafil

In vitro studies

Sildenafil metabolism takes place mainly by cytochrom P450 (CYP) subgroups form 3a4 (main road) and 2C9 (sub -line). Therefore, all agents that inhibit these subgroups can reduce the clearance of Sildenafil and its stimulating agents that can increase Sildenafil's clearance.

In vivo studies

Mobile pharmacokinetic analysis through clinical test data shows that when using Sildenafil simultaneously with CYP3A4 inhibiting agents (such as ketoconazole, erythromycin, cimetidin) will reduce Sildenafil's clearance.

cimetidin (800 mg), a Cytochrom P450 inhibitor and non -specific inhibitor CYP3A4, when used simultaneously with Sildenafil (50 mg) will increase Sildenafil's concentration in plasma to 56% of healthy volunteers.

erythromycin (500 mg, use 2 times/day for 5 days) is an average inhibitor agent CYP3A4, when used simultaneously with a single dose of 100 mg Sildenafil, increasing the area under the Sildenafil curve (AUC) up to 82%. In addition, the simultaneous use of a single 100 mg of Sildenafil with the protease inhibitor of HIV Saquinavir (1200 mg used 3 times/day), this is also a CYP3A4 inhibitor, increasing Sildenafil's CMAX to 140% and increasing AUC to 210%.

Sildenafil has no effect on saquinavir pharmacokinetics. The more powerful CYP3A4 inhibitors such as Ketoconazole and Itraconazole will also have a greater impact.

Single -dose of 100 mg Sildenafil with HIV Ritonavir (500 mg, use 2 times/day), a powerful P450 inhibitor, increasing Sildenafil's cmax up to 300% (4 times) and increased AUC in plasma up to 1000% (11 times higher). 24 hours after taking the drug, the concentration of Sildenafil in plasma is still approximately 200 ng/ml compared to 5 ng/ml when using Sildenafil alone. This is consistent with the obvious effect of Ritonavir on the substrates of P450. Sildenafil did not have any effect on the pharmacokinetics of Ritonavir.

When using Sildenafil at the recommended dose for patients who are treating agents capable of inhibiting CYP3A4, the maximum free Sildenafil concentration in plasma does not exceed 200 nm and well -tolerated. Single doses of antacids (Magnesi hydroxid, aluminum hydroxid) does not affect the bioavailability of Sildenafil.

In a healthy male volunteer study, the concurrent use of endothelin and bosentan antagonists, (an average CYP3A4 touch substance, CYP2C9 and maybe CYP2C19) in a stable state (125 mg, 2 times/day) with Sildenafil in a stable state (80 mg, 3 times/day) leading to reduction 62.6% and 55.4%. Sildenafil increases the AUC and CMAX of Bosentan, respectively 49.8% and 42%. Concentrated with strong CYP3A4 touch substances, like Rifampicin, is expected to reduce sildenafil levels in plasma.

Dynamic pharmacokinetic data in clinical trials shows that CYP2C9 inhibitors (such as Tolbutamid, Warfarin), CYP2D6 inhibitors (such as Serotonin Selective Rehabilitation Inhibitors, 3 -ring anti -depressive drugs), Thiazid diuretic, enzyme inhibitors transferring angiotensin (ACE) and calcium channels that do not affect the dynamics Study by sildenafil.

On healthy men who volunteered, there was no influence of azithromycin (500 mg/day for 3 days) to AUC, CMAX, Tmax, Sildenafil's exhaust rate, and its main metabolites.

The influence of Sildenafil on other drugs

In vitro studies

Sildenafil is a weak inhibiting agent of cytochrom P450 subgroups 1A2, 2C9, 2C19, 2D6, 2E1 and 3A4 (IC50> 150 μm).

Because after the recommended dose, the peak concentration of Sildenafil's plasma is approximately 1 μm, so Sildenafil will not change the clearance of the substrates of these isenzymes.

In vivo studies

Sildenafil has been shown to be able to increase the hypotension of acute and chronic nitrates. So contraindicated use of sildenafil along with substances for nitric oxidation, organic nitrates or organic nitrite in any form, whether it is frequent or interrupted.

In three specific studies on drug-or-interactive interaction, the DOXAZOSIN (4 mg and 8 mg) and Sildenafil (25 mg, 50 mg, or 100 mg) is indicated for patients with stable treatment of prostate tumors with Doxazosin. Observing these subjects, the average additional reduction of blood pressure measured in the back position is 7/7 mmHg, 9/5 mmHg, and 8/4 mmHg and the average additional reduction of measured blood pressure in the vertical position is 6/6 mmHg, 11/4 mmHg, and 4/5 mmHg. When simultaneously indicated Sildenafil and Doxazosin on patients who are being treated stably with doxazosin, few reports on patients with symptomic posture. These reports include dizziness and fatigue, but not fainting. Sildenafil indications for patients who are taking sympathetic alpha canceller can lead to symptomic hypotension in some sensitive patients.

There is no significant interaction when indicated simultaneously with Sildenafil (50 mg) with Tolbutamid (250 mg) or Warfarin (40 mg) (are substances metabolized by CYP2C9).

Sildenafil (100 mg) does not affect the pharmacokinetics of HIV protease inhibitors such as Ritonavir and Saquinavir (both of these drugs are the substrate of CYP3A4) (see above, the effect of other drugs on Sildenafil).

Sildenafil in a stable state (80 mg, 3 times/day) increased 49.8% of Bosentan's AUC and increased by 42% CMAX of Bosentan (125 mg, 2 times/day).

Sildenafil (50 mg) does not increase the time of Aspirin bleeding (150 mg).

Sildenafil (50 mg) does not increase the hypotension effect of alcohol on healthy volunteers with an average maximum concentration of 0.08% (80 mg/dL).

There is no meaning between Sildenafil (100 mg) and amlodipine in hypertension patients (in the back position only lowering 8 mmHg blood pressure for systolic blood pressure and 7 mmHg for diastolic blood pressure).

Analysis based on safety data shows that there is no difference in unwanted effects in patients who use and do not use Sildenafil simultaneously with lowering blood pressure drugs.

Storage

Leave a cool place, avoid light, temperatures below 30⁰C.

To be out of reach of children, read the instructions carefully before use.

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